Paint brush and method of making the same



July 1, 1958 F. c. MAXWELL 2,840,841

PAINT BRUSH AND METHOD OF MAKING THE SAME Filed Oct. 21. 1954 INVENTOR.13 fiafil'iiizi/ifarmeil,

BY Fwd Pau A TTORNEYS.

United States Patent PAINT BRUSH AND METHOD OF MAKING THE SAME FranklinC. Maxwell, Philadelphia, Pa., assignor to Elder & Jenks, Inc.,Philadelphia, Pa., a corporation of Penn- This invention relatesgenerally to paint brush assemblies and more particularly to a paintbrush structure which provides positive retention of the filaments inthe direction of the brush handle.

Paint brushes in common use normally comprise filaments bonded togetherby a glutinous substance at one end, a tubular ferrule in which thefilaments are inserted and a handle inserted in the ferrule at the endopposite to the filaments. The filaments in such brushes are held inplace by the gripping action of the ferrule which is usually metallic,and this grip is augmented by rivets or pins driven through the ferruleand the bonded filaments. Brushes so constructed have a tendency toloosen where the ferrule grips the filaments or to break away in thebonding material because of the action of the rivets or 111118.

Accordingly it is a principal object of this invention to provide apaint brush in which the filaments are positively held in the derictionof the handle without damage to the bonding material which holds thefilaments together.

It is another object of this invention to provide a paint n brush inwhich the bonded filaments are connected directly to the handle by asubstantially rigid retaining membrane.

It is another object of this'invention to provide a method of markingpaint brushes in which the brush is made up of independent units whichare assembled without need of further treatment of the bonding materialwhich holds the bonded filaments in the ferrule.

A paint brush in accordance with this invention includes a handle 11, aferrule 12, a retaining element 14, a resinous capping layer 19, thefilaments 13, andthe filament bonding material 18.

Fig. 1 is aperspective view partially cut away of a brush made accordingto the invention.

Fig. 2 is afragmentary side elevation of the handle and retainingelement of a brush made according to the invention.

Figs. 3-6 are sectional side elevations showing the consecutive stagesin the manufacture of a brush in accordance with the invention.

Fig. 7 is a perspective view of the retaining element made in accordancewith the invention.

The term filament as hereinafter used includes natural pig bristle,nylon, horse hair and any other material normally used in the workingportion of a brush.

The filaments 13 may be any one of the types normally used in paintbrush manufacture including natural and synthetic materials. They aregathered together and are then bonded together at one end by a suitablebonding material 18. Such material may be a natural rubber or syntheticresin or a mixture of both. Where natural pig bristles are used, thebonding material will preferably be pure crude rubber; where nylonfilaments are employed a suitable mixture of natural rubber andsynthetic resin is preferred since the synthetic resin provides a betterbond to the nylon filaments, whereas the pure rubber adheres better tothe metal ferrule. Pure crude rubber is 2,840,841 Patented July 1, 1958substance which is not subject to attack by the paintingmaterials to beemployed with the brush or to boiling water.

The bonding material 18 is applied to the filaments 13 when thefilaments 13 are inserted in the ferrule 12 as shown in Fig. 3. Thequantity of bonding material applied is determined by the depth ofpenetration around the filaments desired and by the viscosity of thebonding material itself. When natural rubber is used the bondingmaterial isvulcanized directly in the ferrule; otherwise it is permittedto harden in place.

When the bonded filaments 13 are in place in the ferrule 12 a layer ofcapping material 19 is poured into the ferrule 12 over the ends of'thebonded filaments 13. This material 19 is characterized by its capacityto harden Without the application of further heat or pressure. When thecapping material 19 is poured into the ferrule 12 there is a limitedmechanical combination with the bonding material 18 used to bind thefilaments 13, and also a certain adhesion to the ferrule 12. The cappingmaterial 19 thus becomes a separate layer attached both to the filamentbonding material 18 and the ferrule 12.

The handle of the brush 11, according to this invention, is of thenormal type except that a T-shaped slot 20 is formed in the bottom endthereof, as shown in the drawings. This slot 20 continues across thefull width of the handle 11 and is shaped to accommodate the upperflange 15 of the retaining element 14. The retaining element 14 is asubstantially rigid structure having an I-beam crosssection in which theupper flange 15 is somewhat narrower than the lower flange 16. The lowerflange 16 is provided with a plurality of perforations 17. The upperflange 15 of the retaining element 14 is inserted in the T-slot 20 inthe handle 11 as shown in Fig. 2. The handle 11 is then inserted in theferrule 12 sufficiently far to place the lower flange 16 in the fluidcapping material. Due to the self-hardening nature of the cappingmaterial 19 no further action is needed to complete the construction ofthe brush other than to nail the ferrule 12 to the handle 11 by means ofthe nails 10. When the capping material 19 is hardened it will be seenthat a positive directional pull is maintained on the filaments 13through the bonding material 18, the hardened capping material 19, themetallic retaining element 14 and the handle 11. Thus the nails 10 maybe eliminated.

It will be appreciated that many diflFerent types'of slot designs may beused to accommodate the upper portion ,of the retaining element 14, andthat a corresponding number of different shapes may be employed in theretaining element itself. The preferred embodiment shown in the drawingshas been found satisfactory in that the T-slot 20 is easily formed andthe i-beam structure can be simply made from a single sheet of flatmaterial. It is essential that the retaining element be firmly held bythe handle and that the lower portion be sufficiently broad to providelow stress concentration in the capping material 19. As shown in Fig. 7the lower flange 16 is pro vided with a number of holes 17 which allowthe capping material 19 to flow around the flange 16.

It has been pointed out above that any self-hardening glutinoussubstance may satisfactorily serve as the capping material 19 in thisinvention. It is preferred, however, in the manufacture of a brushaccording to this invention, that the capping material 19 be capable ofself-hardening at a relatively rapid rate without being a aninstant-setting material which would prevent the pouring of the cappingmaterial during continuous manufacturing operations. It has been founddesirable for manufacturing purposes, to employ a capping material whichwill completely harden within two hours after application but which willretain working fluidity for a minimum period of about thirty-fiveminutes. determined that the preferred, materials for, thispurpose arethe two-part, self-setting reactive resins. In practice the epoxyresinshaving viscosities inthe range between 100 and 100,000 centipoiseshavebeen found to besatisfactory when used with a suitable proprietyamine catalyst such as 8% by weight of diethylene triamine. Alsosatisfactory is a resorcinol resin basewith a suitable aldehyde catalystsuch as 25% by weight of commercial 37% formaldehyde solution. A thirdmaterial 'isbased upon the well-known phenolic resinoids. Therpreferredcatalyst in this case is 7% by weight of hypophosphorus acid. It shouldbe noted that the base resin employed in the latter capping materialisnot stable alone at room temperature. It is of course essential thatthe catalyst employed in each case be well distributed throughout thebase material to insure proper setting.

An important feature of my invention is the method of making the brush.The handle unit, Fig. 2, is assembled as one function; the upper flange15 of the retaining clement14 is inserted in the T-slot 20. Since theT-slot 20 runs the full length of the bottom of the handle 11, theretaining element 14 is simply slid longitudinally along the slot intothe posit-ion shown in Fig. l. The assembled filaments 13 are insertedin the bottom of the ferrule 12 and the desired bonding material 18 ispoured is as shown in Fig. 3. Where the bonding material 18 is naturalrubber, it is vulcanized directly in the ferrule 12. The cappingmaterial is then poured into the ferrule 12 over the filaments 13 andbonding material 18 to form a capping layer 19 of suificientdepth toencompass the lower flange 16 of the retaining element 14. The handle 11and the connected retaining element 14 are then inserted in the ferrule12. The height of the retaining element 14, the height of the ferrule 12and the depth of the capping layer 19 are predetermined to place thelower flange 16 of the retaining element 14 in the capping material 19substantially as shown in Fig. 5. Due to the self-hardeningcharacteristics of the capping material 19 no further operation isneeded on it to complete the brush other than to nail the ferrule 12 tothe handle 11 where necessary. The ferrule 12 may be designed to gripthe handle 11 in any known manner.

Many alternative forms and materials willbe apparent as substitutes forthose shown. Thus it is of course not intended to limit the invention tobrushes which are hand operated. Any type of head element may beemployed for the handle 11. Likewise the invention could be entirelyoperative without the presence of the ferrule 12 as It has been.

astructural element, since directional strength is obtained from theretaining element 14.

It will be appreciated that the above description covers only apreferred embodiment of the invent-ion and that one skilled in the artmay readily make various changes and modification therein withoutdetracting from the invention as hereinafter claimed.

Having thus described my invention I claim:

1. A brush comprising a handle having a slot recessed along the bottomface thereof, a plurality of painting filaments grouped together at oneend, a resinous bonding material disposed about and above the said endof said filaments, a separate layer of self-hardenable resinous plasticmaterial disposed across said bonding material and mechanically attachedthereto, and retaining means having one end inserted in said recessedslot and held in position by said handle, and the other end horizontallyinserted in said separate layer of self-hardenable resinous material.

2. A method .of making a brush comprising inserting a plurality offilaments in one open end of a ferrule, applying a glutinous bondingmaterial to the ends of the filaments in said ferrule, setting thebonding material, recessing a T-shaped slot in the lower part of ahandle member and inserting therein the upper flange of an I- shapedelongated retaining member, placing a mass of self-hardening resin insaid ferrule across and above said filaments, and inserting the handleand retaining element in said ferrule while said self-hardening resin isstill plastic and immersing the lower flange of said retaining member inthe self-hardening resin.

3. A paint brush comprising a handle having a T- shaped slot recessedalong the bottom face thereof, a plurality of painting filaments bondedtogether at one end by a mixture of synthetic resin and natural rubber,a separate capping layer of a two-part self-setting'reactive resindisposed across said bonding material and above the ends of thefilaments, an elongated retaining element of I- shaped cross sectionhaving a narrow upperflange inserted in said T-slot and having a broadlower flange substantially perforate disposed in said separate cappinglayer, and rigidly retained therein when said two-part resin hashardened. I

References Cited in the file of this patent UNITED STATES PATENTS720,051 Moss Feb. 10, 1903 957,331 Hascy May 10, 1910 1,420,925 InghramJune 27, 1922 2,274,002 Saltzman Feb. 24, 1942 2,512,997 Bixler June 27,1950 2,562,716 Hervey July 31, 1951

